Frequency of the most prevalent Thiopurine S-Methyl Trasferase alleles in referrals to Shariati Hospital in Tehran

Patients with low or intermediate TPMT enzyme activity are at increased risk to develop severe hematopoietic toxicity after taking standard doses of thiopuring medications. The aim of this study was to determine the frequency of four allelic variants of the TPMT gene in an Iranian population. In this cross sectional study, samples were obtained from 127 Iranian volunteers in Shariati hospital and were analyzed using PCR-RFLP and Allele Specific PCR techniques to determine the presence of common TPMT Polymorphisms in this population. Mutant TPMT alleles were found in 11.8% of subjects (15 out of 127). Nine had TPMT*2, 4 TPMT *3C and 2 TPMT*3A. Our data showed the necessity of TPMT polymorphisms assessment before administration of thiopurine drugs.